Underwear has the function of supporting, shaping and protecting the breasts, and often not wearing underwear during the developmental period of women will lead to sagging breasts, breast infections, and problems affecting personal aesthetics. 1. Sagging breasts: girls’ breasts are mainly composed of adipose tissue, fibrous tissue, glands and ducts, etc. There is no hardware support, so the natural state is sagging. The underwear will be able to play a role in supporting and shaping the breasts to prevent them from sagging. 2. Breast infection: If we don’t wear underwear, the breasts will frequently rub against the outer garment, which can easily cause breast infection. 3. Impact on personal aesthetics: With the development of female breasts, not wearing underwear will result in obvious bumps, exposing women’s privacy and affecting personal aesthetics. Therefore, it is recommended that developing women develop good habits of wearing underwear, and try to choose fabrics that are skin-friendly and comfortable, and suitable for their own size of underwear.